To make it easier, I’m going to make the fractions so that they both have the same denominator. To do this i have to multiply both the top and the bottom of one fraction by the other fractions denominator for both fractions.
When i do that, I get:
swimming: 8/40
tennis: 15/40
If you add those fractions together, you will get 23/40.
40-23=17 So, 17/40 of students chose cricket.